A computer implemented method is provided for processing a 3D fetal ultrasound image. A 3D fetal ultrasound image is obtained (either acquired or received from memory), and the spine is detected within the image. This enables a first reference axis to be defined. A second reference axis is defined perpendicular to the first reference axis, and the 3D fetal ultrasound image is updated (e.g. rotated in 3D space) using the first and second reference axes and an up/down (elevation) orientation detection. This provides a normalization of the orientation of the image, so that a machine learning approach is better able to identify landmarks within new images.
